Knots are useful in various situations. As an example, knots are often used in fishing to tie a hook to a fishing line or to tie two lengths of fishing line together.
While manually tying such knots is not necessarily difficult, one must first be taught how to tie such knots. In addition, even when one has learned how to tie the knots, it may not be easy to tie them under all circumstances. For example, it may be more difficult to tie a knot when one is on a rocking boat. Furthermore, when one has underdeveloped or compromised motor skills, for example due to age or disability, tying such knots can be challenging.
From the above discussion, it can be appreciated that it would be desirable to have means for assisting people in tying knots.